Phys.org September 27, 2022
An international team of researchers (USA – Gemological Institute of America, Purdue University, University of Wisconsin, Italy, Germany) analyzed a rare diamond, from Botswana, formed 660 meters below the Earth’s surface confirming that ocean water accompanies subducting slabs and thus enters the transition zone (TZ). This means that our planet’s water cycle includes the Earth’s interior. The immense pressure in the TZ causes the olive-green mineral olivine, which constitutes about 70% of the Earth’s upper mantle. The mineral transformations greatly hinder the movements of rock in the mantle. Subducting plates often have difficulty in breaking through the entire transition zone. So, there is a whole graveyard of such plates in this zone underneath Europe. The subducting slabs also carry deep-sea sediments. These sediments can hold large quantities of water and CO2. The dense minerals wadsleyite and ringwoodite can store large quantities of water, in fact so large that the transition zone would theoretically be able to absorb six times the amount of water in our oceans…read more. TECHNICAL ARTICLEÂ https://www.nature.com/articles/s41561-022-01024-y
NiO content of ferropericlase in worldwide super deep diamonds. Credit: Nature Geoscience (2022)